Joint position sense of the knee in healthy female athletes across the menstrual cycle

  Introduction: Tearing of anterior cruciate ligament (ACL) is the most common lower extremity injuries in female athlete. In past studies, the relationship between ACL injuries and levels of sex hormones, as well as the relationship of ACL injuries with neuromuscular system has been proved, but the relationship between neuromuscular control and levels of sex hormones has been less considered. Thus, the aim of this study was to find out any possible such relationship by measuring joint position sense (JPS) of the knee in healthy female athletes across the menstrual cycle.   Materials and Methods: In this quasi-experimental study, 16 healthy female athletes participated voluntarily. Knee JPS was evaluated by reproduction of the target angle, in weight-bearing position at 3 menstrual phases. In each phase, levels of estrogen and progesterone also measured. Knee angles were determined using a system consisting of skin marking, digital photography and software AutoCAD. The absolute angular error was considered as dependent variable.   Result: There was a significant differences between JPS of the knee in 3 phases of menstrual phases (P=0.025), and this difference was more prominent between 1st and 3rd phases (P=0.003).   Conclusion: Findings of this study suggests that accuracy of joint position sense of the knee differs in healthy women athletes across menstrual cycle and the lowest accuracy was found in menstrual phase, when sex hormones are at a minimum concentration.